A 745-mile high voltage electrical cable would carry power under the sea.

A proposed high voltage electrical cable running across the floor of the North Atlantic Ocean to tap Iceland's surplus volcanic geothermal energy would become the world's longest underwater electrical cable, if it goes ahead. The cable would be a significant step towards a pan-European super grid, which may one day tap renewable sources as far afield as Scandinavia, North Africa and the Middle East. It's argued that such a grid would be able to widely transmit energy surpluses from active renewable sources, thereby alleviating the need for countries to use (or build) back-up fossil fuel power stations to cater for peaks in demand when more local renewable sources aren't particularly productive.

If a European super grid comes to fruition, energy surpluses will be big business. So it's hardly surprising that both Germany and the United Kingdom are jostling for position at the other end of the Icelandic cable, with Norway and the Netherlands also having been mooted as potential connectees. That would necessitate a cable at least 745 miles (1198 km) in length, making it easily the longest electrical cable in the world.

The scheme, first proposed in March of last year by Iceland's largest energy producer Landsvirkjun, would aim to export five billion kilowatt-hours of energy per year for an estimated $350 to $448 million return. A feasibility study subsequently carried out has failed to find any terminal difficulties with the idea, and UK energy minister Charles Hendry is set to fly to Iceland in May to woo the relevant authorities.

An electrical link to Iceland is one of several international interconnectors either proposed or in progress in Europe, in addition to the fifteen or so routes that exist already (existing and planned connections can be seen on this map). Norway is a focal point for many of the confirmed forthcoming interconnectors which, unlike the proposed Iceland link, would see a two-way exchange of energy designed to further boost its energy security and that of its neighbors. The country is already linked via four North Sea interconnectors to Denmark, Germany, the UK, and the Netherlands—the latter being the current world record holder for longest submarine power link at 360 miles (580 km).

More ambitious are the proposed DESERTEC and Medgrid schemes to to interconnect countries and renewable energy sources on both the European and African sides of the Mediterranean Sea. German in origin, DESERTEC would involve the investment of more than $500 billion dollars by 2050, into 6500 square miles (nearly 17,000 sq km) of solar thermal collectors (plus a bit of wind) around the edge the Sahara Desert. The scheme could, it's suggested, supply 15 percent of mainland Europe's energy needs. Facts and figures for the French Medgrid scheme (conceptually very similar to DESERTEC) are rather more elusive, and interpretation varies as to whether the two schemes are complementary or in competition.

Conceptual sketch of the proposed DESERTEC energy system.

the Trans-Mediterranean Renewable Energy Cooperation (TREC)

A problem inherent to all long-distance electrical transmission: energy loss due to the resistance of the cables. Thanks to Joule's first law, the problem is minimized by stepping up voltage, with a ten-fold increase resulting in a 100-fold loss reduction. The Norway-Netherlands link transmits AC at 300,000 and 400,000 volts.

Even the proposed Iceland interconnector, accounting for the worst case scenario of a 930-mile (1500-km) cable, falls well within the bounds of profitability according to the findings of a 1980s study which calculated the longest cost-effective distances for electrical transmission to be 2500 miles (4000 km) for AC and 4300 miles (7000 km) for DC. Official costs are yet to be tabled for the project.

The exportation of renewable energy is a logical next step for Iceland, which has done a grand job of getting its own house in order. The country currently meets 81 percent of its energy needs with domestic renewable sources—thanks in no small part to the country's tremendous geothermal assets, sitting as it does on the Mid-Atlantic Ridge (which can have occasional less welcome consequences). The country plans to be free of fossil fuels in the near future.

James Holloway
James is a contributing science writer. He's a graduate of the Open University, with a B.Sc. in Technology and a Diploma in Design and Innovation. Twitter@jamesholloway

I can't speak to the Norway-Netherlands link, if it is in fact AC, but anything over about 400 miles should be DC anyway. That's the point at which DC transmission becomes more efficient than AC high voltage transmission.

Just googled it, the Norway-Netherlands link is in fact DC. I was skeptical when they referred to it as AC in the article. In addition, it is only 360 miles (my hunch was that it would be above the 400 mile mark).

The fascinating part of the bi-directional cables such as the Norway - Netherlands cable is that they have a trading desk attached to it.

The electricity flows from one end to the other based on variable prices, demand and production. If suddenly demand drops or production rises the market responds and the flow can reverse. Especially with some renewable sources where production can be variable, the wind picking up on one end can reverse the flow of electricity.

The pan-European super grid is essentially just one big 24/7 electricity market where power gets traded on supply and demand. Those countries that play their cards right (invest in clean energy sources) can make a nice profit by selling their surplus energy to countries that don't have their house in order.

It also aids resilience. If one country has to temporarily or urgently shut a power production plant down they can just buy the needed power on the market from neighbours in an instant. The hope is that black outs resulting from unfortunate circumstances (emergency shutdown of one plant when another is just undergoing planned maintenance etc.) will be less likely.

I wonder if they will evaluate using a superconducting cable? I don't know much about the technologies involved to know if it's really applicable though. The only ones I'm aware of use liquid nitrogen to keep the cable cold enough to super conduct, which would certainly be a substantial engineering challenge over that kind of distance.

Strange to think that extracting enormous quantities of heat from a few thousand feet down in the earth, taking many megawatts from the wind as it blows, and covering deserts with solar cells has no negative effect on our environment or climate. These so-called renewable agendas sound like madness to me.

In fact, compared to them, nuclear power plants, natural gas turbines, and even coal-fired plants are virtually benign. They take up little space and they do little to alter the natural environment. Their effect on wind flow and sunlight reaching the surface is virtually nil.

Strange to think that extracting enormous quantities of heat from a few thousand feet down in the earth, taking many megawatts from the wind as it blows, and covering deserts with solar cells has no negative effect on our environment or climate. These so-called renewable agendas sound like madness to me.

In fact, compared to them, nuclear power plants, natural gas turbines, and even coal-fired plants are virtually benign. They take up little space and they do little to alter the natural environment. Their effect on wind flow and sunlight reaching the surface is virtually nil.

Beside the fact they belch greenhouse gases into the atmosphere in vast quantities.Now I'm not saying renewables are 100% clean as it costs x amount of greenhouse gases to produce them. they produce negligible amounts in their working life.

Strange to think that extracting enormous quantities of heat from a few thousand feet down in the earth, taking many megawatts from the wind as it blows, and covering deserts with solar cells has no negative effect on our environment or climate. These so-called renewable agendas sound like madness to me.

In fact, compared to them, nuclear power plants, natural gas turbines, and even coal-fired plants are virtually benign. They take up little space and they do little to alter the natural environment. Their effect on wind flow and sunlight reaching the surface is virtually nil.

A coal-fired power station will dump pretty much the same amount of heat into the environment as a geothermal. Although the higher temperatures of a super critical coal plant makes them more efficient, the geothermal plant has no hot flue gases.

Strange to think that extracting enormous quantities of heat from a few thousand feet down in the earth, taking many megawatts from the wind as it blows, and covering deserts with solar cells has no negative effect on our environment or climate. These so-called renewable agendas sound like madness to me.

In fact, compared to them, nuclear power plants, natural gas turbines, and even coal-fired plants are virtually benign. They take up little space and they do little to alter the natural environment. Their effect on wind flow and sunlight reaching the surface is virtually nil.

Erm... It's not like windmills actually halt the wind, you know. There's quite a lot of wind, and it's no more affected by windmills than it is by trees. Are you suggesting we should chop down all trees as well, to avoid them disturbing the wind flow?

Likewise for all the other renewable energy sources. Putting solar cells in a desert will not magically prevent the desert from being warm (and even if it did, I'm not sure I'd see that as a significant problem, given that deserts are largely man-made in the first place) And on Iceland, a lot of heat is escaping from the ground underneath them *regardless* of what they do with it. And there's a lot of it. Using a fraction of it to boil water is hardly going to wreck the environment.

Strange to think that extracting enormous quantities of heat from a few thousand feet down in the earth, taking many megawatts from the wind as it blows, and covering deserts with solar cells has no negative effect on our environment or climate. These so-called renewable agendas sound like madness to me.

In fact, compared to them, nuclear power plants, natural gas turbines, and even coal-fired plants are virtually benign. They take up little space and they do little to alter the natural environment. Their effect on wind flow and sunlight reaching the surface is virtually nil.

Erm... It's not like windmills actually halt the wind, you know. There's quite a lot of wind, and it's no more affected by windmills than it is by trees. Are you suggesting we should chop down all trees as well, to avoid them disturbing the wind flow?

Likewise for all the other renewable energy sources. Putting solar cells in a desert will not magically prevent the desert from being warm (and even if it did, I'm not sure I'd see that as a significant problem, given that deserts are largely man-made in the first place) And on Iceland, a lot of heat is escaping from the ground underneath them *regardless* of what they do with it. And there's a lot of it. Using a fraction of it to boil water is hardly going to wreck the environment.

It does have an effect on surface temperature and wind patterns to pull that much energy out of the atmosphere. The places where these are built aren't generally forested so your point about trees having the same effect is well...irrelevant. Also modern wind turbines are much larger than tress. Anyways, enjoy your science lesson. You can't pull power out of the atmosphere without having an impact.

It does have an effect on surface temperature and wind patterns to pull that much energy out of the atmosphere.

Did you even read the paper? It emphasizes the uncertainty in their simulations even in the Abstract. While interesting, those results alone are too weak to make a positive statement that using wind turbines "does have an effect on surface temperature". What your linked study instead shows is that such an effect in plausible, and that more study is needed to see how strong this effect is.

Strange to think that extracting enormous quantities of heat from a few thousand feet down...

In fact, compared to them, nuclear power plants, natural gas turbines, and even coal-fired plants are virtually benign. They take up little space and they do little to alter the natural environment.

Coal is mined in some areas at depths greater than 1000 feet. Mountains are destroyed to get at coal as well. Natural gas fracking is not so great for ground water. Oil, as you know, may be drilled at at depths greater than 8000 feet. Nuclear power plants have has the potential to make vast stretches of land uninhabitable, poison the seas and crops over thousands of miles. Plus uranium has to be mined and spent rods have to be safely transported and stored.

While doing something always has some effect, geothermal is pretty clean and has great potential.

A coal-fired power station will dump pretty much the same amount of heat into the environment as a geothermal. Although the higher temperatures of a super critical coal plant makes them more efficient, the geothermal plant has no hot flue gases.

Please elaborate. Does a geothermal station produce carbon emissions that trap heat in the atmosphere?

Strange to think that extracting enormous quantities of heat from a few thousand feet down in the earth, taking many megawatts from the wind as it blows, and covering deserts with solar cells has no negative effect on our environment or climate. These so-called renewable agendas sound like madness to me.In fact, compared to them, nuclear power plants, natural gas turbines, and even coal-fired plants are virtually benign. They take up little space and they do little to alter the natural environment. Their effect on wind flow and sunlight reaching the surface is virtually nil.

Oh he's serious alright, a quick look at his posting history reveals a mild conservative shill:global warming denial, Clinton-bashing, disregard for civil liberties, denouncing Wikileaks, belittling atheistsIndividually, these leanings don't reveal much, in concert though, they portray a rather predictable neocon shillbag, I'd wager that he's also for foreign wars, against gay marriage and supports the drug war. Hell, I bet if you checked behind his ears you'd find a serial number denoting his make, model, shill-factory of origin and date of manufacture

Strange to think that extracting enormous quantities of heat from a few thousand feet down...

In fact, compared to them, nuclear power plants, natural gas turbines, and even coal-fired plants are virtually benign. They take up little space and they do little to alter the natural environment.

Coal is mined in some areas at depths greater than 1000 feet. Mountains are destroyed to get at coal as well. Natural gas fracking is not so great for ground water. Oil, as you know, may be drilled at at depths greater than 8000 feet. Nuclear power plants have has the potential to make vast stretches of land uninhabitable, poison the seas and crops over thousands of miles. Plus uranium has to be mined and spent rods have to be safely transported and stored.

While doing something always has some effect, geothermal is pretty clean and has great potential.

" Nuclear power plants have has the potential to make vast stretches of land uninhabitable, poison the seas and crops over thousands of miles. "

Actually gas oil coal hydro and geothermal and asteroid strikes are far more likely to make vast stretches of land uninhabitable, poison the seas and crops over thousands of miles than nuke power. All the worlds energy needs for a thousand years can be supplied by burning the worlds existing nuke waste on site using Gen IV units like the GE Prism. No need to mine uranium or store and transport spent fuel.

How the hell did this turn into a debate over the relative merits of geothermal power? I think the point is that many sources of power can be meshed together using this transcontinental power grid. Anyone who suggests one single source of power can end all our energy woes is selling something.

I was under the impression that AC was easier to transmit at long distances, which was why DC failed in the late 1800's early 1900's. how is it that for distances over x amount DC is easier to transmit or more efficient?

Strange to think that extracting enormous quantities of heat from a few thousand feet down in the earth, taking many megawatts from the wind as it blows, and covering deserts with solar cells has no negative effect on our environment or climate. These so-called renewable agendas sound like madness to me.

Nobody said that it has no negative effect. But it's much smaller compared to the alternatives.

Inkling wrote:

In fact, compared to them, nuclear power plants, natural gas turbines, and even coal-fired plants are virtually benign. They take up little space and they do little to alter the natural environment. Their effect on wind flow and sunlight reaching the surface is virtually nil.

I'm a fan of nuclear power plants myself. I will have no problem to buy/build a house near one. I think the benefits outweigh the risk.

But fossil fuels are a different matter. Even ignoring the CO2 that causes the global warming, living near a coal power plant, especially one without the appropriate filters, is horrible. As in having difficulty to breath horrible. I speak from personal experience.

And you just have to take a look at the problems the Chinese have because of air pollution. In some cities they have to wear face masks.

While you may be right that "Their effect on wind flow and sunlight reaching the surface is virtually nil.", the fact is that the emitted CO2 prevents part of the infrared radiation emitted by the earth from reaching space. Less radiation being emitted results in increased temperature.

The temperature will increase until the infrared radiation emitted into space returns to normal levels, and will level off at that point. But since the CO2 concentration in the atmosphere continues to increase with no sign of slowing, the temperature will continue to increase.

Even after the CO2 content levels off, it will take many years for the temperature to level off. Currently, the energy imbalance caused by the emissions of CO2 and other greenhouse gases is 0.85W/square meter. Since the surface area of the earth is about 510.072.000.000.000 square meters, that means a total of 433,561,200 MW.

To put those numbers into perspective, the average energy use worldwide was about 15TW in 2008. That's only 15,000,000 MW, almost 30 less than the energy imbalance caused by CO2.

So, even if we assume that soon all our energy will be generated from wind, solar and geothermal, any harmful effects would have to be very small compared to those caused by the CO2 we put in the atmosphere by using fossil fuels.

You will also have to take into account that coal plants continuously release radioactive substances into the atmosphere, unlike the nuclear power plants that do so only accidentally. Accidents that can be prevented.

For example the Chernobyl accident was caused by not following the operating procedures, and the Fukushima accident was caused by grossly underestimating the maximum height of tsunami waves.

I also find funny, but also sad, this quote from Walter Marshall, the chairman of Britain’s Central Electricity Generating Board (CEGB):

Quote:

"I have to inform you that yesterday the C.E.G.B. released about 300 kilograms (660 pounds) of radioactive uranium, together with all of its radioactive decay products, into the environment.

Furthermore we released some 300 kilograms of uranium the day before that. We shall be releasing the same amount of uranium today, and we plan to do the same tomorrow.

In fact, we do it every day of every year so long as we burn coal in our power stations. And we do not call that “radioactive waste.” We call it coal ash.

As counterpoint to inkling's droll shilling, consider that the wind-sapping windfarms and sun-sinking solar farms will merely absorb and mitigate (respectively) some of the additional energy that the accelerated greenhouse effect yields. You could call it global-warming-driven power.

Strange to think that extracting enormous quantities of heat from a few thousand feet down in the earth, taking many megawatts from the wind as it blows, and covering deserts with solar cells has no negative effect on our environment or climate. These so-called renewable agendas sound like madness to me.

Earth exists in a thermal equilibrium. The amount of radiation received and emitted is centered around that equilibrium, and the only thing that affect it (barring a gargantuan quantity of energy that prevents it from settling in the equilibrium anytime soon) is greenhouse gasses.

500 billion dollars? With about 40 years to go, and 500 million people in the European Union, that's 1000 dollars, or a measly 25 dollars per person per year. Compare that with the cost of the Iraq war, at 6300 dollars per US civilian. The misallocation of resources by humanity is mindboggling.

Strange to think that extracting enormous quantities of heat from a few thousand feet down in the earth, taking many megawatts from the wind as it blows, and covering deserts with solar cells has no negative effect on our environment or climate. These so-called renewable agendas sound like madness to me.

In fact, compared to them, nuclear power plants, natural gas turbines, and even coal-fired plants are virtually benign. They take up little space and they do little to alter the natural environment. Their effect on wind flow and sunlight reaching the surface is virtually nil.

If you think coal fire plants are clean you need your head examined.The amount of Nitrogen oxides, ash, soot, CO2, Suplur dioxides they put out ranks it the most polluting power generation technology available.

You forget that extraction and minning of coal (open-pit) destroy landscape, literally.

I was under the impression that AC was easier to transmit at long distances, which was why DC failed in the late 1800's early 1900's. how is it that for distances over x amount DC is easier to transmit or more efficient?

The point about AC is that you can transform it to a higher voltage, which can then be more efficiently transmitted than low voltage DC. High voltage DC is even more efficient for transmission than high voltage AC, but the technology to get to high voltage DC was not available in the late 1800's.

Oh he's serious alright, a quick look at his posting history reveals a mild conservative shill:global warming denial, Clinton-bashing, disregard for civil liberties, denouncing Wikileaks, belittling atheistsIndividually, these leanings don't reveal much, in concert though, they portray a rather predictable neocon shillbag, I'd wager that he's also for foreign wars, against gay marriage and supports the drug war. Hell, I bet if you checked behind his ears you'd find a serial number denoting his make, model, shill-factory of origin and date of manufacture